Re: Patches to clean up string-handling corner cases

[Juergen W. <wie...@fr...>]

> Currently the check for single- or double- quotes is made at
> the time a string constant is parsed, as in:
>   A = "1\n2"
>   B = '1\n2'
>   if (A ne B) print "Strings are not equal"

In my opinion, it should be this way.  When I have to choose between
single and double quotes, I take the ones which are more
convenient in the current situation.  I do not want to take into
account what can happen to them later.

Quite a few programming language offer both single and double quotes
having different syntax (bash, perl, ...).  But I'm not aware of a
single one that keeps track wether a given string has been typed in
this or that way.

> But if you assign a value to a string variable via some more
> complex path, including your new system() function, then there
> is no check for whether embedded special characters should be
> given the single-quote treatment (store raw input) or the
> double-quote treatment (add \ in front of certain characters).

It works the way I would want it to have.  You can't input a newline
character directly on the command line, so there has to be a way to
get it into strings nevertheless.  There is no such problem within
pipes.  If I need a newline in the string returned by system(), I'll
use one.  I don't see any need for escape sequences in this case.


> As you can see from the sequence below, it does not
> work to define and invoke a macro on the same input line:
>
> gnuplot> set macros
> gnuplot> foo = "1"; print @foo;  foo = "2"; print @foo
>          warning: foo is not a string variable
>          warning: foo is not a string variable
>
> gnuplot> foo = "1"; print ;  foo = "2"; print
>                           ^
>          constant expression required

I wouldn't really expect this to work.


Juergen